This is a long paper of approximately 85 pages which describes 6 different congenital conditions which do not appear clinically until adulthood, except on very rare occasion. Although the abnormal tissue is present from the time of birth, the morphologic features in each of the 6 conditions: floppy mitral valve, valvular aortic stenosis, discrete subvalvular aortic stenosis, hypertrophic cardiomyopathy, sinus of valsalva aneurysm, marfan syndrome are described in detail.